Scientists discovered evidence of giant otters weighing over 100 pounds that may have lived in China’s Yunnan province six million years ago.
Denise Su—the head of paleobotany and paleoecology at the Cleveland Museum of Natural History—told The Two-Way that the large prehistoric animal was “two to three times larger than any modern otter species.”
In 2010, a team of researchers found a well-preserved cranium of the never-before-seen species in an open lignite mine. The findings on the discovery of the fossilized skull was published in the Journal of Systematic Palaeontology.
The cranium was almost complete, but had been flattened to about an inch and a half thick, according to NPR.
“The bones are pretty fragile, so we couldn’t really reconstruct it physically,” Su said. “So what we did is we took CT scans of the cranium, and then we digitally reconstructed it.”
Previously, scientists had discovered bones from the same species in 2009, including an upper arm bone. Su recalled seeing the large bone and thinking, “This looks like an otter but it’s huge. … Is this really an otter?”
An interesting feature of the newly discovered skull was that the animal’s teeth had “some badger features,” according to Su. This is seen in the latin name for the species—Siamogale melilutra—meles meaning badger and lutra meaning otter
Su explained that scientists can learn more about otters’ evolution from the skull, specifically, their teeth.
The giant otter skull had large budont—or round-cusped—teeth. Researchers questioned whether or not modern species of otters had inherited these teeth from a common ancestor or if they had evolved to have them because of their eating habits through convergent evolution.
Su said that when studying otters, scientists discovered that “these bunodont teeth actually arose at least four different times within the greater otter lineage.” This means that the teeth came from convergent evolution rather than from a common ancestor.
“A lot of times in modern carnivores, the large size is partly due to subduing prey, so their prey is bigger and the carnivores also get bigger,” Su said.
The question researchers still have is that, if the animal probably ate small animals such as mollusks, then “why the big size?”
